My Science School

Songbirds rehearse their melodies by 'singing in their sleep'. Scientists believe that the birds dream of singing to help them hone a range of different tunes. Young birds learn to sing by listening to adults and then practise by listening to their own attempts. Research suggests that songbirds store a song after hearing it, then rehearse it later in their sleep.

The researchers compared the activity of each neuron while the awake bird sang, while a sleeping bird could hear a recording of its own song, and during undisturbed sleep.

While the birds are awake and singing the neurons fire in a pattern that is unique to the note and syllable components of each bird's individual song. When the awake bird hears its own song, these neurons do not fire in response.

But in the sleeping bird listening to a recording of its own song, the neurons do fire in the pattern identical to song production, though the bird produces no sound. This pattern of firing during listening, like the pattern of firing necessary to produce song, actually anticipates the next song "syllable," or set of notes.

"The learned song is a temporal code that uses the nerve impulse spikes of single cells in precisely matched patterns for hearing and singing. The two patterns can be 'mapped' to each other with spike-by-spike precision," said Margoliash. "The bird is using the preceding sound to predict how to generate the next syllable."

Understanding how patterns of behavior are represented in the brain has been a major problem for neurobiologists.

"Previously we found that during singing song is represented as a temporal code. Now, much to our surprise, we find this correspondence in single cells of matched sensory and motor patterns. Forming this mapping of sound and action is the process of learning," said Margoliash.

During undisturbed sleep, the researchers discovered, the neurons spontaneously fired the same complex song production patterns in bursts. Interestingly, these activity patterns were at slight variance, as if the bird was rehearsing a variety of slightly different songs, sometimes with slower or faster tempos.

How does the bird learn to correct its song when by the time it hears it the neuron is now engaged in the production of the next sound? Practice during sleep may be part of the answer.

"In contrast to the prevailing idea that it learns by making moment-to-moment adjustments, we think the bird stores the song production pattern and reads it out at night, an 'offline' solution to the timing problem," said Margoliash. "The zebra finch can replay and strengthen the pattern during sleep."

The next step, according to Margoliash, is to explore what happens to song learning when the sleep replay is interrupted.

"If we can describe the rules by which sleep acts on song learning, these lessons may apply to learning in other animals, including humans," said Margoliash. "Neurobiologists have often found that lessons learned from weird and wonderful animals apply to all animals. The beautiful songs of birds could have much to teach us about how we learn."

Credit : Science Daily 

Picture Credit : Google

Black kites, whistling kites and brown falcons are known as "firehawk raptors". They help spread wildfires in places like Australia by picking up and dropping lit branches or embers onto fresh patches of dry grass so as to scare out small animals. It makes it easier for them to swoop down to catch the fleeing prey.

Ongoing bird research will help answer questions, of course. “There’s loads to find out,” Bonta says, citing recent findings. “We just learned in 2016 that birds’ neurons are packed differently. They’re way smarter than we thought. We’re just beginning to understand avian memory. Crows’ problem-solving ability is amazing. There are a lot of tool-using behaviors.”

Part of the reason Westerners may have trouble accepting the concept of firehawks, Bonta suggests, is our lack of connection to our environment: “Westerners have done little but isolate ourselves from nature,” he says. Yet those who make a point of connecting with our earth in some form—he uses turkey hunters as an example—“have enormous knowledges because they interact with a species. When you get into conservation [that knowledge] is even more important.” Aborginal people “don’t see themselves as superior to or separated from animals. They are walking storehouses of knowledge.”

Credit : Penn State Altoona 

Picture Credit : Google

Memories of 2019 Sambhar tragedy came back to haunt Rajasthan as scores of birds were found dead on the lake. They included different species of birds such as rufous tree pie, owl, crow and gull. Earlier, a week before the bird deaths were reported from Sambhar, 189 demoiselle cranes had died at Jodhpurs Kaparda pond.

Bhopal-based National Institute of High-Security Animal Disease (NIHSAD) confirmed the cause of the bird deaths to be avian influenza (bird flu). The lab has detected two strains of influenza virus - H5N8 and H5N1-in the dead birds.

The H5N1 strain of bird flu can spread from birds to humans through contact. Symptoms of H5N1 include cough, fever, sore throat muscular pain, headache and difficulty breathing. The HSN1 strain can also result in human deaths.

Migratory birds were under observation in Jodhpur and other areas following these bird deaths Security was beefed up in the Desert National Park as well, which is home to the critically endangered Great Indian Bustard.

What happened in 2019?

In a similar incident in 2019, over 30,000 migratory birds died in Rajasthan, especially in the locality of Sambhar Lake. But the cause was found to be avian botulism. Avian botulism is a serious neuromuscular illness caused by a toxin produced by the bacterium clostridium botulinum. The outbreak at Sambhar was caused by various factors such as a good monsoon which created a favourable environment for the bacteria to thrive.

What is bird flu?

Bird flu is a highly infectious, respiratory disease in birds caused by the H5N1 influenza virus, which can occasionally infect humans and other animals that come into contact with a carrier. Bird flu usually affects poultry such as chicken and ducks. The other strain H5N8 is highly lethal among birds, but it has not been found to affect humans.

How does it spread?

Bird flu spreads when birds come into contact with nasal secretions and faeces of infected birds. It can spread to humans in a similar fashion.

Symptoms in birds

Lack of energy and appetite: swelling of the head, eyelids, combs; discolouration of legs: nasal discharge, coughing, sneezing and diarrhoea are symptoms observed in birds affected by avian flu. It is often fatal.

Symptoms in humans

If humans are affected by bird flu, they may show symptoms such as diarrhoea, high fever, chest pain, muscle pain, cough and headache.

Picture Credit : Google

Mia, a bearded vulture, is the world's first bird to get a prosthetic foot. In large birds, the loss of a limb results in the inability to walk and ultimately leads to death from malnutrition. A detachable prosthesis for avian limbs is unsuitable given the extreme loads. They have to withstand in daily use. For the first time, a technique known as osseointegration (direct skeletal attachment) was used on a vulture, and a custom implant mounted directly into Mia's leg bone. It can now land and walk using both feet, making it the first 'bionic bird".

A team of veterinarians, led by Sarah Hochgeschurz of the University of Veterinary Medicine, Vienna, contacted Aszmann for help. Aszmann is an expert in limb reconstruction, but such a procedure had never been performed on a bird.

Designing a prosthetic limb for a predatory bird presented a number of unique challenges. A detachable prosthetic would not have been durable enough to withstand the daily punishment a raptor would subject it to. Any prosthesis would have to be able to not only grip prey but also withstand the shock of such a big bird landing.

So the team designed Mia a custom implant that would be mounted directly into the leg bone. 

Using a technique called osseointegration, the surgeons installed a metal anchor into Mia's leg bone where her ankle used to attach. Over time, the bone grows into the metal threads on the anchor, "integrating" the metal rod into Mia's skeleton. 

The team then attached her prosthesis to the anchor. Instead of being shaped like an artificial bird foot, the vulture's bionic leg is a black rubber cylinder that makes Mia  look like she accidentally stepped on a sushi roll. It's designed to allow Mia to grip both surfaces and prey but also to act as a shock absorber for softer landings. The cylindrical design is intended to minimize the potential of her twisting and damaging her leg when it got caught on branches, and the metal anchor integrated into the bone will provide Mia a high level of tactile feedback, Aszmann said. The team described the procedure in a study published June 11 in the journal Scientific Reports.

The surgery required anesthetizing Mia for more than two hours but it was a success.

Credit : Live Science 

Picture Credit : Google

Antarctic Petrel is a seabird that lives and breeds in the southern oceans, and on the Antarctic islands. Its plumage is partly brown, partly white. The head, sides, throat and back are brown.

The bill is black and the feet are yellow. It has an elongated nostril indicating a well-developed sense of smell which is an unusual feature to be found in birds. Its diet includes krill, fish, and small squid.

It is a highly social bird. They roost on icebergs in flocks that have thousands of birds. It is known for producing foul-smelling stomach oil that it uses to feed itself on long flights, feed its young via regurgitation and to spray at predators.

The movement of Antarctic petrels is generally dependant on their reproductive cycles. Breeding and nest-building take place on the coasts of these islands, and they act as the central place for foragers during the breeding period. Since the population of the female bird is more than that of the male bird, some of the females are unable to mate every season. Their breeding starts in winter; they lay their eggs towards the end of November, and then the females incubate their eggs for two months. After their eggs hatch, the parents feed the chicks, and the chicks flee the nest after around three to four months. During this time, petrel parents must be aware of the south polar skua (Stercorarius maccormicki) as these birds are natural predators to their eggs and young ones.

Picture Credit : Google

Like animals, birds too bear the brunt of climate change. Previous studies have shown how climate change affects birds migration, nesting, hatching and feeding habits. A recent study has shown how birds are evolving to develop smaller bodies and longer wingspans in order to adapt to the changes.

Published in the journal Science Advances, the study analysed the body size of birds in the Amazonian rainforest. Researchers analysed data collected on more than 15,000 birds that were caught, measured, weighed, and tagged over the course of 40 years of field work. In all, the scientists investigated 77 species whose habitats ranged from the cool, dark forest floor to the sunlit warm areas.

Lighter, but longer

Researchers found that nearly all the birds had become lighter since the 1980s. Most species lost an average of two per cent of body weight every decade, meaning a bird species that would have weighed 30 grams in the 1980s would now average 27.6 grams. A third of species simultaneously had developed longer wings, driving a decrease in mass to wing ratio. The birds that are known to fly more and are exposed to heat for longer, had the most pronounced changes in body weight and wing size.

But why?

The changes are thought to be a response to nutritional and physiological challenges, especially during the June to November dry season. The team hypothesised that this was an adaptation to utilise their energy better as they are now forced to travel longer to find food and shelter. Climate change has decreased the availability of fruit and insect resources for birds.

Longer wings, and a reduced mass-to-wing ratio, produce more efficient flight similar to how a glider plane with a slim body and long wings can soar with less energy.

A higher mass-to-wing ratio requires birds to flap faster to stay aloft using more energy and producing more metabolic heat Reduced size is perhaps beneficial under climate warming as the birds can cool themselves better. The data was not tied to a specific site but rather collected from a large range of the rainforest, meaning the phenomenon is ubiquitous. Researchers expressed that even the wildest parts of the Amazon untouched by humanity are being impacted by climate change.

Picture Credit : Google